# decorator add
# 装饰器只能带一个参数
def logging(flag):

    def decorator(mufunc):

        def fun_in(a, b):

            if flag == '+':
                print('正在加法计算')
            elif flag =='-':
                print('正在减法计算')

            c = mufunc(a, b)
            return c

        # 有返回
        return fun_in

    return decorator


@logging('+')     #  add =  decorator(add)
def add(a, b):
    c = a + b
    return c


@logging('-')     #  add =  decorator(add)
def sub(a, b):
    c = a - b
    return c


result = add(10, 20)
print(result)
result = sub(10, 20)
print(result)